Three women, aged 19, 21, and 30 years, two with the Peutz-Jeghers syndrome (PJS), had unilateral ovarian tumors composed of Sertoli cells with abundant eosinophilic cytoplasm. Electron microscopical and immunohistochemical examinations in one case supported the diagnosis of a sex cord tumor. Two patients are well 3 and 20 months postoperatively; the third was well for 15 years when recurrent tumor involving multiple intraabdominal sites was discovered. The occurrence of two of these tumors in patients with PJS and the known increased frequency of sex cord tumors in patients with this syndrome indicate an association. Sertoli cell tumor should be included in the differential diagnosis of oxyphilic ovarian tumors, particularly if there is a tubular pattern.